cifs: release leases for deferred close handles when freezing

We should not be caching closed files when freeze is invoked on an fs
(so we can release resources more gracefully).

Fixes xfstests generic/068 generic/390 generic/491

Reviewed-by: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>